HR: 0800h
AN: U41A-0809    [Abstracts]
TI: Effects of Permafrost Degradation on the River Transport of Solutes to the Kara Sea
AU: * Frey, K E
EM: frey@ucla.edu
AF: University of California, Los Angeles, Department of Geography 1255 Bunche Hall, Los Angeles, CA 90095-1524 United States
AU: Siegel, D I
EM: disiegel@syr.edu
AF: Syracuse University, Department of Earth Sciences 204 Heroy Geology Laboratory, Syracuse, NY 13244-1070 United States
AU: Smith, L C
EM: lsmith@geog.ucla.edu
AF: University of California, Los Angeles, Department of Geography 1255 Bunche Hall, Los Angeles, CA 90095-1524 United States
AB: Measurements of solute concentrations from watersheds located throughout West Siberia suggest that warming and permafrost degradation will amplify the transport of dissolved solids to the Kara Sea and adjacent Arctic Ocean. We present concentrations of Ca²⁺, K⁺, Mg²⁺, Na⁺, Si, Cl^-, SO₄^2-, HCO₃^- and total dissolved solids (TDS) from 94 streams and rivers within the Ob'-Irtysh, Nadym and Pur river drainage basins. The sampled sites cover an area of ~10⁶ km², span a large climatic gradient (~55-68°N), and incorporate 39 permafrost-influenced and 55 permafrost-free watersheds. Our results show that TDS concentrations of waters in permafrost-free watersheds average ~289 mg L^-1, in contrast to only ~48 mg L^-1 in permafrost-influenced watersheds. This difference may occur because permafrost forms a confining barrier that both inhibits the infiltration of surface water through deep mineral horizons as well as restricts mineral-rich subpermafrost groundwater from reaching surface water pathways. A principal components-based end-member mixing analysis supports the premise that mineral-rich groundwater is the primary source of solutes to rivers in permafrost-free watersheds, whereas mineral-poor peat surface water is the primary source in permafrost-influenced watersheds. We estimate that should permafrost in the region completely disappear, the TDS exported from the West Siberian region to the Kara Sea would increase by approximately 60% (from its current value of ~46 Tg yr^-1 to ~73 Tg yr^-1). Such an increase in dissolved solid delivery to the Kara Sea could have important implications for future biological productivity in Eurasian Arctic shelf waters.
DE: 0702 Permafrost (0475)
DE: 1065 Major and trace element geochemistry
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1621 Cryospheric change (0776)
SC: Union [U]
MN: Fall Meeting 2005